Radiofrequency apparatus



June 15 1 19260 'J. A. VICTOREEN RADIOFREQUENGY APPARATUS Filed April 30,. 1926 glvwento'c W attoxmq 5 Patented .lnne' l, .192.

JOHN AUSTIN-VICTOREEN, 0F CLEVELAND, @EIG.

namornneunncr m: i

TUE.

Application filed April 30, 1826. Serial Ho. 305,880.

My invention relates to radiofrequenc? apparatus and relates particularly to sup high frequency tuning apparatus comprising an electrical coil of substantially constant inductance to a given high fre uency y is particularly applicable for use in radio systems in high frequency amplifying circuits and is particularly a plicable to such systems employing radlo fiers of constant frequency.

An object of the present invention is to provide for radio systems, an improved transforming apparatus comprisin an inductance coil and a variable con enser so constructed as to be capable of bein inexpensively manufactured as a unit an which permits approximate tuning to the frequency of current in the system by adjustment of the variable condenser portion thereof, I

Another object of my inventionis to provide a transforming unit as aforesaid in a casing containing the inductance and capacity components and in which the electri- -,-cal constants of the components may be varied by adjustable movement.

' c0 resistanceratio may be varied by moving a.

Another ob -ect is to construct a device for the coupling of vacuum tubes and their associated circuit-s which will effectively prevent self-sustained oscillation of the tubes and their circuits. 1

Another object is to provide a device of the class described including inductance and conductor in adjustable relation thereto.

Other objects of my invention and the invention itself will-become apparent as the following description of an embo iment of my invention. progresses, and in which description reference will be had to the drawings accompanyin this specification and which are a part t iereo'f. v H Referring now to the drawings,- Fig. 1 shows a side elevation of an em bodiment of my invention, a portion of the outer casing thereof being shown as broken away to expose certain of the inner parts.

trical circuit in w requency ampli- A eac intermediate the concave sheets 6 and 17 Fig. 2 showsa section taken on the line- 2-2 of Fig. 3.

Fig. 3 shows an end view of the embodiment of Fig. 1.

Fig.4 shows a section taken on line H of Fig. 3.

Fig. 5 shows a plan view of portion of the apparatus.

the condenser,

Fig. Gshows an end view of the condenser I portion.

Fig. 7 shows a portion of a typical elecich the apparatus of my invl'pntion may be employed.

1 my invention, Fig. 9 being taken on line 9-9 of Fig. 8.

Referring now to the difi'erent figures of the drawings in all ofwhich like parts are designated by like referencecharacters, at

.1 is shown a cylindrical casing having and walls 2 and 3, the end walls being clamped onto the ends of the cylindrical casing portion by a threaded rod 4. and damping nuts 5 and 6 on each end ofthe rod.

The cylindrical cusin 1 is positioned with reference to the end we is 2 and 3 by flanges 7 and 8 on the end walls and projecting therefrom as shown. The end walls 2 and 3 are centrally perforated to admit the bolt 4.

At 9 and 10 I show a pair of electrical "coil windin or inductances carried on bob bins 11 an 12, respectively, the winding 9 being preferably the primary winding of an electrical transformer for high frequency currents andthe winding 10 being the sec-' a pair of nuts 13 and 14 threaded onto the rod 4 and clamping the bobbins between them. a v Y Atlt, 1'2 and 18 I show me pcriorated centrally, the sheets bein concave-convex and with their concave sides "facin other and the sheet 18 [disposer and irradiated therefrom by insulating di 19 and 20 of mice 0 other insulatin material. e iate m tallic a set 18 opposite.

gs. 8 and 9 show a modified form of 7 aeeaeoe may be, and preferably'is, sho wn in the form than the diameter 0? of a disc asmay be also the sheets 16 and 17, which, however, are shown as being, in

r the embodiment illustrated, rectangular, in

form.- I a The metallic sheets 16 and 17 in the embodiment illustrated are in electrical contact with the nuts 14 and 21 and perhaps also with the rod 4 on which the nuts. 14 and 21 are carried, whereas the metallic late 18 has a central openin 22 of larger iameter lated from the rod l, the two plates 16 and 17, and the plate 18 forming the condenser. The two plates 16 and 17 are electrically connected to the twoterminals of the electrical winding 10, connection'being made preferably to the conductor plate 18 by a soldered connection at the periphery of the plate 18v with a circuit conducting wire 23, a tap 24 4 leading therefrom to the outside terminal of the winding 10, the inside terminal being connected by a tap to thecnut 14 and thence through therod 4. The capacity of the condenser is varied by turning the nut 21 on the rod 4 to compress orto restore from compression the concave-convex plates 16 and 17 so as to var the mean effective distance between the p ates 16 and 17 and the intermediateplate 18 over their entire "area. Binding ostterminals 26, 2 7, 28 and.

29 are provide being carried on the end wall 2 which is made ofinsulating material,

- there being circuit conductors such as the circuit conductors 30 and 31 leadin from the terminals of the windings 9 an 10 to connect these windings to the bindin post-s. It is understood that a pair of the inding posts such as the binding posts 26 and 27 will be connected to the wlnding 9, and a pair of binding posts such as the binding now 'in' use I have turns of wire.

posts 28 and 29 will beconnectedto the winding 10, there being also connected the two conductors of the condenser to the latter two binding posts.

Referring now to the circuit diagram of Fig. 7 showing a portion ofa radio circuit in which my invention may be used, at 13 is shown the primary winding of the trans former and at 14 the secondary thereof, each comprising a large number of/turns of wire,

the exact number of turns, however, being variable and depending largely upon the frequency of alternating current adapted to traverse the windings. When the apparatus of my invention is .applied to the better known forms of rlradio-amplifying systems found that I secure'very goods results usin for the winding 9, 200 turns of wire, an forzthe winding 10, 300

When using such windings the efficiency of the'circuit is increased considerably b fconnecting the condenser; electrode in -m "tiple across-the 300 turn co Since h the rod 4 and is insu-' for the transformer also in part such oscillations and thereby ren ers the tributed capacity in the coil is insufficient to completely balance the inductance thereof to the frequency of-current commonly employed in such systems; the capacity of I the added variable condenser is sufiicient to minals of the apparatus, the latter leadingto theaudion amplifying tube 35, which has associated therewith a filament energizing battery Aand an amplifying battery B according toth e'usual practice. 1

At 36 I show the output terminals for the complete apparatus comprising the apparatus of my invention associated with the audion tube and energizing batteries.

The apparatus of my invention is es ecial- 1y adapted to be inserted in the amplifying units such as shown in Fig. 7 of a radiofrequency amplifying system. The apparatus/of my invention comprises a transformer having a resonant curve which is many times sharper than the other ty es of transformers commonly employe By making the resonant curve of great sharpness selectivity isaccomplished and more over the 'useof an aperiodic primary coil is possible. I

My device prevents self sustained oscillations in the vacuum tubes and their'associated circuits, because, I believe, of the combination of a transformer and a suitable conductor suitably disposed in the field thereof, for example, as described,and as shown by the drawings, but I have found that the use of an aperiodic primary coil revents system more stable. However, whether the primary coil or inductance be aperiodic or not, the device described and shown permits the potentiometer such as 40 to be used solely as a volume control and not as a losser. f

The conductor 16, being aperiodic due to its shape, and disposed so as to cut a portion' of the field of the transformer as shown, acts to dampen the circuit and to reduce greatly the inductance of the transformer, thereby changing the ratio of reactance to resistance and due to its relatively low resistance caus'ng any losses to be sustained in the interna circu t comprising the transformer rather than in the ex 'ternal circuit comprising the conductor. It

may be, however, that very little loss is menses with that of the inductance and its circuits.

In Figs. 8 and 9 I have shown a device resembling. in o eration the device of Figs.

1 to 6 but di ering therefrom in certain structural respects.- These fi ures show a casin 1, end walls 2 and 3, and clamping nuts 5 and 6 thereon as shown in Figs. 1 to 6. In place of the bobbins 11 and 12, I show a bobbin 4l having spaces and secondary inductances or for prime M coils 42 an 43 respectivel the bobbinv being shown as composed 0 assembled discs of insulating material on certain of which discs 44 the wire is wound between the other discs 45. The coils 42 and 43 are thus assembled with their axial openings in aligmment.

A plurality of aperiodic conductors of relatively low resistance are assembled at the endof the coils. As shown there are two such conductors 46 in the form of brass plates or sheets each perforated near its edge as at 48 to pass onto rod 4 where they are clamped in rotatably adjustable position and are adjustable toward and away from the coils as by nuts 49 and 49, Shims (not shown) may be used with either or both nuts 49 and 49 or the plates 46 may be bent to suitably adjust their position in the field of the windings or coils. These plates ex tend across the axial openings or air cores of the coils and may be rotated into various sitions as indicated by the full and dotted ines in Fig. 9.

Nut 49 also serves to fix the position of the bobbin on the rod 4. An additional nut 49" engages the condenser plate 16 and in conjunctionwith nut 21 serves to adjust the position of the condenser on rod 4. Such adjustment of the condenser relative to the bobbin and coils may be desirable to ob tain the correct amount of change in the re actance-resistance ratio of the inductance when the conductors 46 are omitted, since.

the brass plate 16 then performs the functions of the conductor 46- in addition toits functions as a plate of the condenser.

In eithercase, however, the self sustained oscillations ofthe tubes and their circuitsare prevented and the desired reactance-re- SlStflIlCB ratio of'the 1nductances is obtained when the conductor (either plates 46, or .glate 16) is of suitable size and "is suitably readed rod 4 able for the desired purposes. In Figs. '8

and 9 the effective size of conductors 46 may be adjusted thereb obtaining the. desired results or, when p ates '46 are omitted, the plate l6'may be brought into thessuitnuts 49 and 21. The condenser comprisin inclusive is substantially th struction and manipulation as the corresponding condenser of Figs. 1 to 6.

able position with respect to the coils by ale. 16'to- 21- e same in- ;con-

n will be evident tothose skate at the I art that I have provided apparatus possessin many desirable propertles and character1stics.- By means ot my invention 1 am enabled to manufacture on a commercialscale ratio frequency a paratus each comprising a self-contal'ne inductance and a condensen'tuned at the factory and fixed to operate at apredetermined frequency. h oreover, each apparatus is so constructed that self-sustained oscillations in the circuit are prevented; An additional feature of my invention is that tubes having different internal capacities may be employedmith the a paratus without apprecmbly aiiecting tiie resonant frequency of the ,ap aratus. In other words, an apparatus em odying my invention and comprising agiven inductance and condenser tuned to a, determined frequency may be employed without appreciable effect on the resonant frequenc' with tubes having relatively widely varying internal capac1ties. It will be understoo' from the toning description and the d awings that the con- "shown and described herein and to be employed as a dampener of oscillation is of a suflicient size to exert the desired amount of damping on the circuit of which the inductance is a art.

The con uctor 16, or conductors 46, act to change the reactance-resistance ratio of and dampen the inductance and its circuits to the extent of preventing self-sustained oscillations of the vacuum tube and its circuit,- but this change and dampin to the extent of undesira ly affecting or impairing the resonant characteristics of the tube and itscircuit. Moreover'the'action of such conductor is to set' u counter forces which, due tothe relativelygow resistance of the conductor, are almost equal to the apis not carried'on I plied forces, and as a result the circuit con tains only suficientexcess'of positive resist:

'ance to insure stability.

' his application is a continuation in part of my cope'nding application, Serial No. 1

727,853, filed July 24th,'1924.

Although I have disclosed in this applicationmy inventions of method as well as apend. said bobbins being telescoped over said;

' oscillation a being rigidly secured to one o rod, the said threaded end of the said rod projecting beyond the bobbins, a pair of suitable condenser plates disposed in tube reventing position in the .field of the win ings on the bobbins and co-ax- I ially of the rod, a 'threaded nut reciprocable on the threaded end of the rod and adapted to flex one of said condenser plates to vary the electrostatic capacity between the lates, air of end walls for thecasin said rod said'end walls and supporting the other end wall, transformer windings on the bobbins and electrical circuit connections connecting the condenser plates in multiple with one of said transformer windin s.

2. In apparatus 0 the class described, the combination with an enclosing casin bobbins disposed in axial alignment wit 1n the casing, a rod having a threaded end, said bobbins being telescoped over said rod, the said threaded end of the said rod pro'ecting beyond the bobbins, a pair of suitable condenser plates disposed in tube oscillation preventing position in the field of the windings on the bobbins and co-axially of the rod, one of said plates being of concavoconvex form and of inherent resilient metallic material, a threaded nut reciprocable on the threaded end of the rod and'adapted to flatten said concavo-convex condenser plates to vary the electrostatic capacity between the plates, a pair of end walls for the casing, said rod being rigidly secured to one of said. end walls and supporting the other end wall, transformer windings on the bobbins and electrical circuit connections connecting the condenser plates in multiple with one of said transformer windings.

3. In apparatus of the class described the combination with an enclosing casing, hobbins disposediin axial ali nment within the casing, a rod having a threaded end, said bobbins bein telescoped over said rod,'the said threaded end of the said rod projecting beyond the bobbins, a pluralit of suitable condenser platesdi'sposed in tu e oscillation preventing position in the field of the windings on the bobbins and co-axially of the rod, two of said plates being concavo-convex resilient metallic plates, and an intermediate plate being] insulated from theraea soe 7 adapted to flatten said concavo-convex condenser plates tovary the mean efi'ective distance between the concavo-convex plates to .and the intermediate plate, a pair of end walls for the casing, said rod rigidly securing the said end walls to the side walls of the casing, transformer windings on the bobbins, electrical circuit connections connecting the condenser plates in multiple with one of said transformer windings.

la In a transforming unit for radio fre quency amplifiers of constant frequency, the combination with a pair of transformer windings axially dis sed with reference to 4 each other, one of t 1e said windings being an aperiodic primary winding and the other windin being a secondary winding, a oasing enc osing the said windin and supporting the same, a variable can enser secured within the casing and disposed axially and in tube oscillation preventing position in the field of the winding, said condenser comprisin a pair of oppositely dished metallic" p ates and an intermediate plate insulated therefrom, and variably adjustable means adapted to variably flex the dished plates to vary the electrostatic capacity between the plates. s v

5. In a transforming unit for radio frequency amplifiers, the combination with a pair of transformer windings each having an air core axially aligned-with reference to each other, a suitable variable condenser disposed axially of the windings at a predetermined tube oscillation preventing position within the field thereof and extending across the. said air core, the condenser being. adjustable to vary the electrostatic capacity thereof, andia casing, housing and supporting the said windings andcondenser.

6. In a transforming unit for radio frequency amplifiers, the combination with a pair of transformer windings in inductive relation to one another and havin air cores, of a suitable variable condenser isposed in tube oscillation preventing position in the field of the winding and extending across one of the cores, the condenser being adjustable toward and away fromone of the windings, the condenser also being adjustk able to vary its electrostatic capacity. 7. In a transformin unit for radio am-. plifiers, 'the combination with a pair of aligned transformer windings in inductive relation to onev another, of a suitable conductor of such area and size as to be capable of preventing tube oscillation disposed in tube oscillation preventin position in the field of the windin s and of such low resistance as compare with that of/the windings as to keep resistance losses at a minimum.

plifiers, the combination with a pair of transformer windings in inductive relation to one another, of a suitable conductor of such area and size as to be capable of preventing tube oscillation disposed in a posi tion in the field predetermined for the prevention of self-sustained oscillationsin the windings, and of such low resistance as compared with that of the windings as to keep resistance losses at a minimum.

9. In atransforming unit for radio'amplifiers, the combination with a pair of transformer windings in inductive relation, to one another, of a suitable conductor com-'- posed of a plurality of parts disposed in. tube oscillation preventing sition in the field of theyvindin and ad ustable to vary the effective area 0 the con uctor. i

10. In a transforming unit for radio amplifiers, the combination with a pair of transformer windings in inductive relation to one another, of a suitable conductor composed of a plurality of parts disposed in tube oscillation preventing position in the field of the -wind1ngs and adjustable to vary the efiectivearea of the conductor, the conductor being adjustable toward and away from the windings.

11. In a trans orming unit for radio amplifiers, the combination with a pair of transformer windings in inductive relation to one another, of a suitable conductor composed of a plurality of parts disposed in tube oscillation preventing position in the field of the windings and adjustable to vary the effective area of the conductor, and a variable condenser disposed adjacent to the windings and adjustable to vary its electrostatic capacity.

12. In a transforming unit for radio amplifiers, the combination with a pair of aligned transformer windings in inductive relation to oneanother, of a suitable conductor adjustably disposed in tube oscillation preventing position in the field'of the windings, and a variable condenser disposed adjacent to the windings and adjustable to vary its electrostatic capacity.

In testimony whereof I hereunto aflix my signature this 29th day of April, 1926.

JOHN-AUSTIN VICTOREEN. 

